Regulatory device comprising a threshold valve control valve

ABSTRACT

The invention relates to a regulatory device for a pump ( 2 ), whose delivery volume can be adjusted, said device comprising a control valve unit ( 3 ) for regulating a control pressure that operates in a control pressure chamber ( 21 ) of an actuator ( 4, 5 ). The control valve unit ( 3 ) comprises a threshold value control valve ( 22 ) and a delivery flow control valve ( 23 ). The threshold value control valve ( 22 ) is subjected to a pressure from a working line ( 7 ) on the delivery side and the delivery flow control valve ( 23 ) can be subjected to a consumer input pressure taken from a consumer supply line ( 8 ), at a comparison pressure connection ( 29 ). In addition, the delivery flow control valve ( 23 ) is subjected to a control pressure that counteracts the consumer input pressure, at a regulatory pressure measurement connection ( 27 ). A control pressure feed connection ( 38 ) of the delivery flow control valve ( 23 ) can be connected to the working pressure line ( 7 ) on the delivery side in a variable manner, by means of the threshold value control valve ( 22 ).

The invention relates to a regulatory device to control a deliveryvolume for a pump with adjustable delivery volume.

A regulatory device for adjusting the delivery volume of a pump in theform of a hydrostatic piston machine is known from DE 43 29 164 A1, inwhich the delivery volume of the hydrostatic piston machine is regulatedby both the delivery side working line pressure and the consumer inputpressure supplied to the consumer after a choke point is supplied to theregulatory unit as input parameters. The regulatory unit comprises twocontrol valves arranged in a valve block which are each pressurised on afirst measurement surface with the delivery-side working line pressure.In the opposite direction a spring acts on a first control valve and theconsumer input pressure taken from the consumer supply line acts on thesecond control valve. The control valves are set so that the firstcontrol valve pressurises a control pressure chamber of an actuator fromthe working line when a limit value which can be set by the spring isexceeded. By pressurising the control pressure chamber the hydrostaticpiston machine is adjusted in the direction of lower delivery.

Below the threshold value the regulation is performed by the secondcontrol valve where the control pressure chamber of the actuator iseither pressurised from the working line or pressure-relieved againstthe tank volume. In this control range, a constant pressure ratio ismaintained between the delivery-side working pressure and the consumerinput pressure. As the pressure difference between the working line andthe consumer input is proportional to the delivery volume, with thecircuit described the hydrostatic piston machine can be regulated to aconstant delivery volume.

The regulatory device has the disadvantage that as the consumer inputpressure diminishes, the second control valve pressurises the controlpressure chamber of the actuator so that the pressure in the workingline can fall to almost zero. If further consumer or control deviceswhich require a minimum pressure are connected to the working line,these devices can no longer be operated.

The object of the invention is to create a regulatory device to set aconstant delivery volume of a pump which maintains the minimum pressurein a working line irrespective of the consumer input pressure.

This object is achieved by the regulatory device according to theinvention with the features of claim 1.

The regulatory device according to the invention has the advantage thatdifferent input pressures are used to control a first and a secondcontrol valve which together constitute the regulatory unit. By dividingthe task between a threshold value control valve and a delivery flowcontrol valve, it is possible to define a first control range in which aminimum pressure can be set by the threshold value control valve, and toprovide a second control range in which above a limit value defined bythe threshold value control valve a constant delivery quantity of thepump can be set by the delivery flow control valve. The constantdelivery quantity is regulated by the delivery flow control valve as afunction of the consumer input pressure and a pressure present at ameasurement surface, where the pressure present is the output pressurefrom the threshold value control valve. This prevents, on diminishingconsumer input pressure, the control pressure chamber of an actuatorbeing pressurised by the delivery flow control valve until the deliveryvolume of the hydrostatic piston machine is set at zero.

The sub-claims define advantageous refinements of the regulatory deviceaccording to the invention.

An exemplary embodiment of a regulatory device according to theinvention is shown in the drawings and explained in more detail in thedescription below. This shows:

FIG. 1 a hydraulic circuit diagram of a regulatory device according tothe invention; and

FIG. 2 a section through a control valve unit according to the inventionarranged in a control valve block.

FIG. 1 shows a hydraulic circuit diagram of the regulatory device 1according to the invention. The regulatory device 1 acts on the swivelangle of an adjustable pump in the form of a hydrostatic piston machine2. To adjust the swivel angle a control valve unit 3 is provided bymeans of which the control pressure predominating in a return element 5can be regulated. The return element 5 sets the swivel angle of thehydrostatic piston machine 2 which is driven via a drive shaft 6.

The hydrostatic piston machine 2 delivers a pressure medium into aworking line 7. Via the working line 7 the pressure medium reaches aconsumer supply line 8 to which is connected a consumer not shown.Between the working line 7 and the consumer supply line 8 are arrangedin series a choke 9 and an adjustable choke 10. The choke 9 need not bedesigned in detail but can be produced by the choking effect of the linelength. Also connected with the consumer supply line 8 is a pressurelimiting device 11. The consumer supply line 8 can be depressurised to atank volume 13 via the pressure limiting device 11, depressurisationoccurring when the pressure in the consumer supply line 8 rises above athreshold value which can be prespecified by means of an adjustmentspring 12.

In the exemplary embodiment shown the swivel angle of the hydrostaticpiston machine 2 is adjusted by means of an actuator 4 and the returnelement 5. Alternatively, the actuator 4 can be omitted and anadjustment in the direction of greater deflection can be generated by aspring acting on the return element 5.

The actuator 4 is connected with the working line 7 via a connectingline 14. The pressure predominating in the working line 7 is thussupplied to a pressure chamber 15 of the first actuator 4, where itco-operates with the force of a pretension spring 16 on a control piston17. The force applied to the control piston 17 in the control pressurechamber 15 of the first actuator 4 is directed so that it adjusts thehydrostatic piston machine 2 in the direction of greater swivel angles.

The control valve unit 3 sets a control pressure which acts in thesecond actuator 5. To regulate the control pressure, the control valveunit 3 is connected by means of a further connecting line 18 with theworking line 7 on one side and with the consumer supply line 8 via aconsumer input pressure supply line 19. Via the further connecting line18 and the consumer input pressure supply line 19, the control valveunit 3 is supplied with the pressure predominating before and after thechoke points 9 and 10 respectively. The control valve unit 3 thusregulates on the basis of the falling pressure at the choke points 9 and10.

The control valve unit 3 is connected via a control pressure line 20with a control pressure chamber 21 which is arranged in the actuator 5.The control pressure predominating in the control pressure chamber 21acts on a control piston 42 and adjusts the hydrostatic piston machine 2in the direction of smaller swivel angles.

As already indicated, instead of the first actuator 4 a spring can bearranged in the second actuator 5 which subjects the control piston 42to a force acting against the pressure of the control pressure chamber21.

The control valve unit 3 comprises a threshold value control valve 22and a delivery flow control valve 23. The threshold value control valve22 is pretensioned with a first spring 24 so that in the pressurelessstate it is in the starting position shown in FIG. 1. The delivery flowcontrol valve 23 is also pretensioned by a second spring 25 and is alsoin its starting position in the pressureless state. The threshold valuecontrol valve 22 has a delivery pressure measurement connection 26 wherethe pressure present at the delivery pressure measurement connection 26opposes the force of the first spring 24. As the pressure rises, thethreshold value control valve 22 is deflected from its starting positiontowards its second end position.

To deflect the delivery flow control valve 23 from its startingposition, the force of the second spring 25 is directed opposite thehydraulic force generated by the pressure present at a control pressuremeasurement connection 27. In the delivery flow control valve 23, theforce of the second spring 25 is supplemented by a force acting on acomparison pressure connection 29. Normally, the pressure of theconsumer supply line 8 acts on the comparison pressure measurementconnection 29, which pressure is supplied via the consumer inputpressure supply line 19 to the measurement surface at the comparisonpressure measurement connection 29.

The control pressure measurement connection 27 of the delivery flowcontrol valve 23 is connected via a control pressure channel 30 with thethreshold value control valve 22. In the starting position of thedelivery flow control valve 23 preset by the adjustable second spring25, a first control pressure connection 31 of the delivery flow controlvalve 23 is connected with a relief line 32 which is connected to apressure relief connection 33 of the delivery flow control valve 22. Therelief line 32 is connected with the tank volume 13.

The threshold value control valve 22 has a second control pressureconnection 34 and a third control pressure connection 35 via which thecontrol pressure chamber 21 is connected via the control pressure line20 with the first control pressure connection 31 of the delivery flowcontrol valve 23. In the starting position of the delivery flow controlvalve 23 therefore the return pressure chamber 21 is connected with thetank volume 13. The pressure taken via the further connecting line 18from the working line 7 is supplied firstly to the delivery pressuremeasurement connection 26 and secondly, via a line branching from thesupply line, to a delivery pressure input 36 of the threshold valuecontrol valve 22. The delivery pressure input 36 is connected in thesecond end position of the threshold value control valve 22 with adelivery pressure outlet 37. The delivery pressure outlet 37 isconnected via the control pressure channel 30 with both the controlpressure measurement connection 27 and with a control pressure supplyconnection 38.

If because of a rising pressure in the control pressure channel 30, thecontrol pressure measurement connection 27 is subjected to a higherhydraulic force and hence the delivery flow control valve 23 adjusted inthe direction of its second end position, the control pressure supplyconnection 38 is connected with the first control pressure connection 31so that the return pressure chamber 21 is pressurised from the workingline 7 via the threshold value control valve 22 and the delivery flowcontrol valve 23. Between the control pressure line 20 and the reliefline 32 is arranged a further adjustable choke 39.

In the pressureless state, first via the pretension spring 16 of theactuator 4 the hydrostatic piston machine 2 is swivelled to a greatdelivery volume. If the hydrostatic piston machine 2 is driven via thedrive shaft 6, this generates a pressure in the working line 7 which issupplied via the connection line 14 in the control pressure chamber 15of the first actuator 4. The first actuator 4, as the pressure in theworking line 7 increases, therefore attempts to adjust the hydrostaticpiston machine 2 further in the direction of greater swivel angles. Therising pressure in the working line 7 is supplied via the furtherconnecting line 18 to the threshold value control valve 22 and subjectsthe delivery pressure measurement connection 26 to a hydraulic force. Asalready stated, in the starting position of the threshold value controlvalve 22 and the delivery flow control valve 23, the control pressurechamber 21 of the second actuator 5 is connected with the tank volume 13so that no force is generated by the second actuator 5 to counter thecontrol force of the first actuator 4.

The pressure in the working line 7 present at the delivery pressuremeasurement section 26 moves the threshold value control valve 22 in thedirection of its second end position and thus, at a limit value presetby the adjustable spring 24, connects the delivery pressure input 36with the delivery pressure output 37. This regulatory pressure suppliedto the delivery flow control valve 23 above the limit value alsoregulates the delivery flow control valve 23 in this range. The deliveryflow control valve 23, as the control pressure rises, is moved furtherin the direction of its second end position by the pressurisation of thecontrol pressure measurement connection 27 so that via the controlpressure supply connection 38, and subsequently via the first, secondand third control pressure connections 31, 34 and 35, the controlpressure chamber 21 is subjected to a control pressure.

The control pressure chamber 21 is pressurised with a control pressureas described above a limit value adjustable via the threshold valuecontrol valve 22 for the pressure in the working line 7, so that areturn force countering the control force of the actuator 4 is onlygenerated above a particular minimum pressure in the working line 7.This measure maintains a minimum pressure in the working line 7 even ifthe pressure in the consumer supply line 8 falls to zero. Above thelimit value the control pressure in the control pressure chamber 21 isset via the delivery flow control valve 23 so that at the delivery flowvalve 23 a force equilibrium is set. The force equilibrium is composedof the force of the second spring 25 and the two hydraulic forces whichact on the control pressure measurement connection 27 and the comparisonpressure connection 29. Above the pressure preset by the threshold valuecontrol valve 22 thus a return control force is regulated with which aconstant pressure difference is set between the working line 7 and theconsumer supply line 8. A constant pressure difference is hereequivalent to a constant delivery volume.

Also provided in the consumer input pressure supply line 19 is ashut-off valve 40, which in normal operation connects the consumersupply line 8 with the comparison pressure connection 29. The shut-offvalve 40 can be activated via a control lever 41 so that the comparisonpressure connection 29 can be connected via the consumer input pressuresupply line 19 with the tank volume 13. Activation of the control lever41 leads to a pressure relief at the comparison pressure connection 29.As a result, the force applied to the control pressure measurementconnection 27 at the delivery flow control valve 23 predominates so thatthe control pressure chamber 21 is pressurised and the hydrostaticpiston machine 2 is adjusted in the direction of a smaller swivel angle.As a result of the adjustment the pressure in the working line 7 fallsand with it the hydraulic force acting on the threshold value controlvalve 22 in the delivery pressure measurement connection 26. Under theforce of the first spring 24 the threshold value control valve 22 isconsequently adjusted in the direction of its starting position so thata lower pressure is supplied to the control pressure channel. Due to thelower control pressure supplied via the control pressure channel 30 tothe control pressure measurement connection 27, the delivery flowcontrol valve 23 is also adjusted in the direction of its startingposition so that the control pressure chamber 21 is depressurised to thetank volume 13 when the working line pressure falls below the thresholdpressure. Thus in the working line 7 there always predominates a minimumpressure which can be preset by the setting of the threshold valuecontrol valve 22. This can be utilised to operate further controldevices or further consumers which require a minimum pressure.

One application, for example, is in mobile devices where the control ofthe mobile valve is supplied via pressure reducers from the workingpressure and their function must be retained even on standby.

A preferred constructional embodiment is shown in FIG. 2. The thresholdvalue control valve 22 and the delivery flow control valve 23 arearranged in a control valve block 43. In the control valve block 43 ismade a first receiver bore 44 and a second receiver bore 45, the centreaxes of the receiver bores 44 and 45 being preferably aligned parallel.Arranged in the first receiver bore 44 is a threshold value controlvalve piston 46 and in the second receiver bore 45 a delivery flowcontrol valve piston 47. The threshold value control valve piston 46 andthe delivery flow control valve piston 47 are smaller in their radialextension than the respective diameters of the first receiver bore 44and the second receiver bore 45 respectively, and arranged axiallydisplaceable in the receiver bores 44 and 45.

The delivery flow control valve piston 47 at its ends has a first guidesection 48 and a second guide section 49, where the radial extension ofthe guide sections 48 and 49 corresponds to the radial extension of thesecond receiver bore 45 so that the delivery flow control valve piston47 is guided in the receiver bore 45. Between the first and second guidesections 48 and 49 on the delivery flow control valve piston 47 isprovided a control section 50 at which are formed a first control edge51 and a second control edge 52.

Between the first guide section 48 and the control section 50, becauseof the different radial extensions of the delivery flow control valvepiston 47 and the second receiver bore 45, a control pressure chamber 53is formed. Furthermore, between the control section 50 and the secondguide section 49 can be provided a further guide section 55.

The threshold value control valve piston 46 is formed corresponding tothe delivery flow control valve piston 47 and has a first guide section56 and at its second end a second guide section 57 with which thethreshold value control valve piston 46 is guided in the first receiverbore 44. Between the first guide section 56 of the threshold valuecontrol valve piston 46 and a control section 58 of the threshold valuecontrol valve piston 46 is also formed a delivery pressure chamber 61 bythe different radial extensions of the threshold value control valvepiston 46 and the first receiver bore 44. The control section 58 of thethreshold value control valve piston 46 also has a first control edge 59and a second control edge 60.

On the face of the first guide section 56 is formed a first pressurechamber 63 which is connected via an overflow channel 62 with thedelivery pressure chamber 61. The pressure predominating in the deliverypressure chamber 61 subjects the threshold control valve piston 46 on aface 64 with a hydraulic force which acts in the axial direction on thethreshold value control valve piston 46.

In the opposite direction, the force of the first spring 24 which restson a spring bearing 65 acts on the threshold value control valve piston46, the spring bearing 65 being actively connected with the thresholdvalue control valve piston 46. For this, a seat 66 is formed on the faceof the second guide section 57, where the spring bearing 65 has a recesscorresponding to the seat 66. On the other end of the first spring 24 isarranged a counter bearing 67 which rests on a set screw 68.

By turning the set screw 68, the distance between the spring bearing 65and the counter bearing 67 can be varied so that the pretension of thefirst spring 24 can be set. To fix the set screw 68 a lock nut 69 isprovided. Furthermore, the open end of the set screw 68 is covered witha cap nut 70 and hence protected from soiling. The lock nut 69 and thecap nut 70 are each sealed via a sealing element, preferably an 0-ring71, against a housing component or against each other. The counterbearing 67, the set screw 68, the lock nut 69 and the cap nut 70together form an adjustment device 72.

To receive the first spring 24, a spring chamber 73 is provided in thecontrol valve block 43. In the control valve block 43, parallel to thefirst and second receiver bores 44 and 45, is made a connecting bore 74starting from the spring chamber 73. The connecting bore 74 opens into atank connecting bore 75, where a tank connecting piece 76 is on theoutside of the control valve block 43. Connected to the tank connectingpiece 76, for example, is a return line not shown which is connectedwith a tank volume 13.

Also on the outside of the control valve block 43 is provided a deliverypressure connection 78. At the delivery pressure connection 78, thepressure supplied via the further connection line 18 from the workingline 7 is passed to the control valve block 73. The delivery pressureconnection 78 is connected with a delivery pressure channel 79 whichopens into the delivery pressure chamber 61.

The function described above of the regulatory device 1 will be brieflyexplained again with reference to the design embodiment in FIG. 2. Whenthe pressure in the working line 7 rises, this increased pressure ispassed on via the delivery pressure connection 78 and the deliverypressure channel 79 to the delivery pressure chamber 61. The deliverypressure chamber 61 is connected with the first pressure chamber 63 sothat the increased pressure of the working line 7 acts on the face 63 ofthe threshold value control valve piston 46. In order to form the firstpressure chamber as a closed volume, the first receiver bore 44 issealed with a closing piece 83, where the closing piece 83 is preferablyfixed with a screw connection in the control valve block 43. A sealingelement 84 is provided as a seal.

Due to the pressure predominating in the first pressure chamber 63, thethreshold value control valve piston 46 is subjected to an axial forcewhich moves the threshold value control valve piston 46 in FIG. 2 to theright against the force of the first spring 24. This moves the firstcontrol edge 59 on the control section 58 of the threshold value controlvalve piston 46 also to the right where, on passing of a threshold valuewhich can be set via the adjustment device 72, it releases a flowchannel from the delivery pressure chamber 61 to the control pressurechannel 30. In addition to the force of the first spring 24, thepressure predominating in the spring chamber 73 of the tank volume 13acts on the threshold value control valve piston 46.

The pressure medium supplied via the control pressure channel 30 to thecontrol pressure chamber 53 is passed via a further overflow channel 80to the second pressure chamber 81 which is formed on the face of thedelivery flow control valve piston 47 and in which the pressure exerts aforce on the face 82 of the delivery flow control valve piston 47. Toform a closed volume, the second receiver bore 45 is also fitted with aclosing piece 83 and a sealing element 84, where the closing piece 83 isalso secured with a screw connection in the control valve block 43.

According to the control pressure supplied via the control pressurechannel 30, the delivery flow control valve piston 47 is deflected fromits starting position shown in FIG. 2 towards the right until a forceequilibrium has been set between the control pressure acting on the face82 and the opposing forces. On the second guide section 69 of thedelivery flow control valve piston 47 is arranged a further springbearing 94 which is actively connected with the tapered seat 93 of thedelivery flow control valve piston 47. A second spring 25 rests on thefurther spring bearing 94, where the second spring 25 can also besupplemented by an additional spring 25′ which also rests on the furtherspring bearing 94. At the opposite end, the second spring 25 and theadditional spring 25′ rest on a counter bearing of a further adjustmentdevice 95 which is constructed corresponding to the adjustment device 72and which will not be described further.

The second spring 25 and the additional spring 25′ are arranged in aspring chamber 96. The spring chamber 96 is connected via a consumerinput pressure supply line connection 97 and a consumer pressure channel98 via the consumer pressure supply line 19 described in FIG. 1 with theconsumer pressure channel 98. Against the hydraulic force acting on theface 82 of the delivery flow control valve piston 47, in spring chamber96 act both the forces of the two springs 25 and 25′ and a hydraulicforce proportional to the consumer input pressure as long as theshut-off valve 40 is not operated.

As long as these forces are smaller than the force applied by thecontrol pressure on the delivery flow control valve piston 47, thedelivery flow control valve piston 47 is moved to the right from itsstarting position shown in FIG. 2. By the movement to the right, thefirst control edge 51 releases a flow channel from the control pressurechamber 53 into a control pressure channel 85. The control pressurechannel 85 is formed as a bore in the control valve block 43. At thesame time as a formation of a flow path from the control pressurechamber 53 to the control pressure channel 85, the second control edge52 of the delivery flow control valve piston 47 interrupts a flow pathbetween the control pressure channel 85 and the tank connection bore 75.The tank connection bore 75 and the control pressure channel 85 areconnected together in the starting position of the delivery flow controlvalve 23 by the different diameters of the delivery flow control valvepiston 47 and the second receiver bore 45.

The control pressure channel 30, the control pressure channel 85 and thetank connecting bore 75 are made as bores in the control valve block 43.The three bores lie in one plane and are connected together via theconnecting bore 74, where the connecting bore 74 is divided into severalsections. Between the tank connecting bore 75 and the control pressurechannel 85 is formed a second section of the connecting bore 74, andbetween the control pressure channel 85 and the control pressure channel30 a third section of the connecting bore 74. In the control pressurechannel 85 is inserted a first stopper 86 which has a blind bore 87 fromthe control pressure channel 85. In the radial direction the stopper 86has a choke opening 88 and a connecting opening 89. Via the connectingopening 89 a flowable connection is created between the third section74b of the connecting channel 74 and the set pressure channel 85 via theblind bore 87. The choke opening 88 however by twisting the stopper 86is brought into partial overlap with the second section 74 a, the firstsection, of the connecting bore 74 so that here an adjustable choke isformed between the set pressure channel 85 and the connecting bore 74.

The control pressure channel 30 also formed as a bore in the controlvalve block 43 is closed with a further stopper 90 in which a furtherblind bore 92 is made from the outside, where the further blind bore 92is connected via a further connecting opening 90 with the third section74 b of the connecting bore 74.

Pressurisation of the actuator 5 described in FIG. 1 takes placestarting from the movement described above of the threshold valuecontrol valve piston 46 and the delivery flow control valve piston 47from the set pressure channel 85 via the blind bore 87 and theconnecting opening 89 and the third section 74 b of the connecting bore74, then via the connecting opening 91 and the further blind bore 92from where a line section not shown which corresponds to the controlpressure line 20 in FIG. 1 leads to the set pressure chamber 21 of theactuator 5.

Activation of the shut-off valve 40 leads to a reduction of the pressurein the further spring chamber 96. The resulting setting movement of thedelivery flow control valve piston 47 to the right is prevented by thefalling pressure in the working line 7, as the first control edge 59 onthe control section 58 of the threshold value control valve piston 46closes the flow path between the delivery pressure chamber 61 and thecontrol pressure channel 30.

The pressure in the second pressure chamber 81 is relieved via the chokeopening 88 into the tank volume 13 so that the delivery flow controlvalve piston 47 is moved in the direction of its starting positionbecause of the forces of the two springs 25 and 25′. The return movementof the delivery flow control valve piston 47 causes the second controledge 52 of the control section 50 to release the flow path from thecontrol pressure channel 85 to the tank connecting bore 75. The controlpressure chamber 21 is thus depressurised into the tank volume 13 sothat as described in FIG. 1, the control force opposing the actuator 4is relieved and hence the swivel angle of the hydrostatic piston machine2 set so that a particular minimum pressure predominates in the workingline 7.

1. Regulatory device for a pump (2) with adjustable delivery volume,with a control valve unit (3) to regulate a control pressure acting in acontrol pressure chamber (21) of an actuator (4, 5), where the controlvalve unit (3) comprises a threshold value control valve (22) subjectedto the pressure of a delivery-side working line (7), and a delivery flowcontrol valve (23) which is pressurised at a comparison pressureconnection (29) with a consumer input pressure taken from a consumersupply line (8) and at a control pressure measurement connection (27)with a control pressure countering the consumer input pressure,characterised in that a control pressure supply connection (38) of thedelivery flow control valve (23) can be connected variably by thethreshold value control valve (22) with the delivery-side workingpressure line (7).
 2. Regulatory device according to claim 1,characterised in that when the pressure falls below a threshold valuewhich can be set via the threshold value control valve (22), the controlpressure chamber (21) of the actuator (4, 5) is connected with the tankvolume (13).
 3. Regulatory device according to claim 2, characterised inthat when the threshold value is exceeded, the control pressure chamber(21) of the actuator (4, 5) can be connected variably with thedelivery-side working line (7) depending on the pressure differencebetween the control pressure present at the control pressure measurementconnection (27) and the consumer input pressure.
 4. Regulatory deviceaccording to any of claims 1 to 3, characterised in that the controlpressure acting in the control pressure chamber (21) of the actuator (4,5), as the control pressure resetting the delivery volume of the pump(2), acts on a first actuator (4) of the actuator unit (4, 5). 5.Regulatory device according to claim 4, characterised in that theactuator unit (4, 5) comprises a second actuator (5) which ispressurised with the pressure of the delivery-side working line (7) andadjusts the pump (2) in the direction of greater delivery volumes. 6.Regulatory device according to any of claims 1 to 5, characterised inthat the threshold value control valve (22) comprises a threshold valuecontrol valve piston (46) loaded with a first spring (24) and thedelivery flow control valve (23) comprises a delivery flow control valvepiston (47) loaded with a second spring (25), the threshold valuecontrol valve piston (46) and the delivery flow control valve piston(47) being arranged in a common control valve block (43), where a firstface (64) of the threshold value control valve piston (46) is arrangednext to a first pressure chamber (63) which is connected with a deliverypressure chamber (61), and where the delivery pressure chamber (61) canbe connected with the control pressure channel (30) via a first controledge (59) formed on the threshold value control valve piston (46). 7.Regulatory device according to claim 6, characterised in that a secondface (66) of the threshold value control valve piston (46) ispressurised in a first spring chamber (73) with the pressurepredominating in the first spring chamber (73) and the first springchamber (73) is connected with the tank volume (13).
 8. Regulatorydevice according to claim 6 or 7, characterised in that a first face(82) of the delivery flow control valve piston (47) is pressurised in asecond pressure chamber (81) with the pressure predominating in thecontrol pressure channel (30).
 9. Regulatory device according to claim8, characterised in that the second face (93) of the delivery flowcontrol valve piston (47) is pressurised in a second spring chamber (96)with the pressure predominating in the second spring chamber (96) andthe second spring chamber (96) can be connected with the consumer supplyline (8).
 10. Regulatory device according to any of claims 6 to 9,characterised in that in the control valve block (43) is formed acontrol pressure channel (85) which is closed with a stopper (90) and inthe stopper (90) is provided a connecting opening (89) and an adjustablechoke point (88), where via the connecting opening (89) the controlpressure channel (85) is connected with a control pressure connectionand via the adjustable choke (88) the control pressure channel (85) isconnected with the tank volume (13).
 11. Regulatory device according toclaim 10, characterised in that the control pressure connection isformed in a second stopper (90) and the second stopper (90) closes thecontrol pressure channel (30).
 12. Regulatory device according to claim10 or 11, characterised in that the control pressure channel (30) opensinto a control pressure chamber (53) which can be connected variablywith the control pressure channel (85) via a second control edge (51)formed on the delivery flow control valve piston (47).
 13. Regulatorydevice according to any of claims 6 to 12, characterised in that thepretension of the first and/or second spring (24, 25, 25′) can beadjusted with an adjustment device (72, 95).
 14. Regulatory deviceaccording to any of claims 1 to 13, characterised in that the comparisonpressure connection (29) of the delivery flow control valve (23) can beconnected via a switch valve (40) with the tank volume (13).